The context was wrt the OpenMPI version that is bundled with a specific
version of CentOS Linux which my IT folks are about to install on one of
our servers. Since the most recent 1.4 stream version is 1.4.3, I'm
afraid that 1.4-4 is really some variant of 1.4 (i.e., 1.4.0) and hence
not that new.

> I've encountered a supposed OpenMPI version of 1.4-4. Is the hyphen a
typo or is this syntax correct and if so what does it mean?

Is this an RPM version number? It's fairly common for RPMs to add "-X" at
the end of the version number. The "X" indicates the RPM version number
(i.e., the version number of the packaging -- not the package itself).